1. Field of the Invention
The present invention relates to a portable terminal device which can change a use style.
2. Description of the Related Art
There are known a sound source direction extrapolation technique of extrapolating the direction of a sound source from sounds acquired by a microphone array including a plurality of microphones, and a sound source separating technique of canceling ambient noise based on the extrapolated direction of the sound source.
For example, Non-patent Document, “Auditory Ability of Human-Symbiotic robots ‘EMIEW’” by Masahito TOGAMI, Akio AMANO, Hiroshi SHINJO, Ryota KAMOSHIDA, Junichi TAMAMOTO, and Saku EGAWA by the Japanese Society for Artificial Intelligence, Oct. 14, 2005, pp. 59-64”, discloses a sound source direction extrapolate technique and a sound source separation technique using a microphone array. The techniques disclosed in Non-patent Document can separate voices of a speaker from ambient noise.
The techniques disclosed in Non-patent Document are adapted to, for example, cellular phone terminals or the like to contribute to the improvement of the quality of talking. When a plurality of microphones are arranged to line in the thicknesswise direction of a cellular phone terminal, for example, the position of a sound source present in the thicknesswise direction can be extrapolated by using the techniques disclosed in Non-patent Document, and voices supplied from other directions as noise can be attenuated based on the extrapolated position of the sound source.
A portable terminal device, such as a cellular phone terminal, is desired to be small-sized, light and thin. This often makes it difficult to form a microphone array by arranging a plurality of microphones on a single casing so as to line in the thicknesswise direction of the portable terminal device. In such a case, it is effective to form a microphone array by distributing microphones to a plurality of casings.